JPH05333794A - Dot matrix type display device with light emitting diode - Google Patents

Abstract

PURPOSE:To enable the information recognition from many directions by improving the directional characteristic of the dot matrix type display device with light emitting diodes. CONSTITUTION:The front ends of the resin parts of the respective light emitting diodes of the dot matrix type display device with the light emitting diodes constituted by disposing the plural light emitting diodes 9 in a dot matrix form on a printed circuit board 3 are formed to a plane shape and the respective light emitting diodes are partitioned from each other by reflectors 10. In addition, an antidazole material 12 is applied on the front end faces of the resin parts of the respective light emitting diodes, by which the light emitting state of the light emitting diodes is made into multiple directions and the visual field angle is widened. External light is irregularly reflected by the front end faces of the diodes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dot matrix type light emitting diode display device in which visible light emitting diodes for emitting light in the visible region are arranged in a dot matrix.
Specifically, it relates to the improvement of its directional characteristics.

[0002]

2. Description of the Related Art FIG. 6 is a sectional view showing a structure of a conventional dot matrix type light emitting device. In the figure, 1 is a full-mold type visible light emitting diode, 2 is a reflector, and 3 is a printed circuit board to which leads 4 of the light emitting diode 1 are connected.

As shown in FIG. 7, the light emitting diode 1 has a structure in which a semiconductor chip 6 is mounted on a metal lead frame 5 and sealed with a resin portion 7. The resin portion 7 is made of a material whose refractive index is larger than that of air, has a spherical tip as shown in the figure, and has a condensing function like a convex lens.

Such all-mold type visible light emitting diode 1
Emits light at the semiconductor chip 6, and the semiconductor chip 6 and the light emitting point are used as synonyms in the following description.

Each of the light emitting diodes 1 is partitioned by a reflector 2, and the reflector 2 functions as a reflecting plate, and the reflector 2 and the light emitting diode 1 are separated from each other.
And the light emitting diode 1 is completely submerged with respect to the tip position of the reflector 2, and by covering the resin portion 7 of the diode from the side surface, the light leaking to the periphery is condensed in the center. Play a role.

In the conventional dot matrix type light emitting device described above, the light emitting point 6 and the resin portion 7 are connected to the optical axis 8 connecting the apexes of the spherical surface.
The emphasis was on increasing the luminous intensity above.

That is, the light emitting diode 1 has a light emitting point 6 in the vicinity of the focal point of a resin part 7 having a convex lens effect in a resin having a high refractive index, and the light from the light emitting point is collected at the tip of the resin part 7. The light is emitted and emitted substantially parallel to the optical axis 8. Moreover, as described above, the resin portion 7 is submerged in the reflector 2, and the leaked light is emitted substantially parallel to the optical axis.

A dot matrix type light emitting diode display device having such a conventional structure is provided with a diode diameter of 8 mm, 5 ×
When the directional characteristics of the display device having a dot matrix configuration of No. 7 were measured by JIS C7036 "Light emitting diode measuring method (for display)", the directional characteristic diagram of FIG. 8 was obtained.

Here, an arbitrary point on the light emitting surface of the diode display device is set as an emission center, and the optical axis 8 passes through the emission center.
When the luminous intensity on a straight line parallel to is set to 100%, the angle of the photometer is changed to the left and right, and the difference between the left and right when the relative luminous intensity reaches 50% is defined as the "viewing angle".

As shown in FIG. 8, the viewing angle of the device having the conventional structure is about 30 degrees, and it is difficult to transmit the display information to a person who exists outside this angle range.

[0011]

In recent years, it has become possible to manufacture large-sized light-emitting diodes with the improvement of light-emitting diode manufacturing technology, and a dot matrix light-emitting diode display device has been realized by combining these. These display devices are installed to transmit information to an unspecified large number of people who are present in relatively distant places, but in such an application, the viewer is on the optical axis 8. It is rare that the displayed information is read at the position, and it is required that the information can be read from any angle.

However, in the display device having the above-mentioned configuration, the viewing angle is as narrow as 30 degrees, and the configuration is focused on improving the light intensity on the optical axis 8. Therefore, the front surface of the device, that is, the optical axis 8 There is a problem that it is difficult for a person who does not exist in the vicinity to read the information.

In view of the above situation, the present invention provides a dot matrix type light emitting diode display device having a wide viewing angle and capable of transmitting information to a wide range of people.

[0014]

SUMMARY OF THE INVENTION The present invention is a dot matrix type light emitting diode display device in which a plurality of light emitting diodes are arranged in a dot matrix on a printed circuit board. The present invention is characterized in that each light emitting diode is partitioned by a reflector, and an antiglare material is applied to the front end surface of the resin portion of the light emitting diode.

[0015]

The light emitted from the light emitting point inside the resin portion of the light emitting diode is refracted and scattered in various directions by the tip portion of the resin portion to widen the viewing angle, and the antiglare material diffusely reflects the light coming from the outside. Facilitates the person's recognition.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a dot matrix type light emitting diode display device according to an embodiment of the present invention, taken along a plane parallel to the optical axis of the light emitting diode.
In the figure, the same parts as those shown in FIG. 6 are designated by the same reference numerals,
The description is omitted.

The tip of the resin portion 11 of the light emitting diode 9 is a flat surface, and the tip of the reflector 10 is aligned with the line connecting the light emitting points 6 of the respective light emitting diodes 9.

FIG. 3 shows a light emitting state of the light emitting diode 9 when the tip of the resin portion 11 is a flat surface. FIG. 3 shows
Light emitted from the light emitting point 6 is refracted in multiple directions according to Snell's law.

The light emitted from the light emitting point 6 inside the resin portion 11 of the light emitting diode 9 is refracted and scattered in multiple directions by the plane of the tip of the resin portion 11 and has a large viewing angle.
The reflector 10 has a function of holding the light emitting diodes 9 from the side and making the optical axes of the respective diodes parallel to each other, but the tip of the reflector 10 is aligned with the line connecting the light emitting points 6 of the respective light emitting diodes 9. This maximizes the luminous efficiency of the entire device. This is the reflector 10
Collects light leaking from the light emitting point 6 to the center,
This is because the light emitted above the light emitting point 6 is not blocked.

FIG. 2 shows another embodiment, in which an antiglare material 12 is applied to the tip surface of the resin portion 11 of the light emitting diode 9. As the antiglare material 12, a transparent matting material is suitable. Since the tip of the light emitting diode 9 is flat, the sun
Reflection of the surface occurs due to external light from a fluorescent lamp or the like, but if the external light has a high illuminance, the diode plane portion may illuminate and the matrix characters may not be readable. Therefore, by applying the antiglare material 12 to the tip surface of the light emitting diode 9, the light coming from the outside is diffusely reflected, and the blinking state of the light emitting diode 9 can be easily recognized.

FIG. 4 is a directional characteristic diagram of the dot matrix type light emitting diode display device according to the other embodiment, and it can be seen that the viewing angle is improved to 120 degrees.

FIG. 5 is a table showing the directivity of a light emitting diode using a semiconductor element that emits light of different wavelength regions belonging to green, red and orange in the other embodiment.
For the measurement, a display device in which light emitting diodes with a diameter of 8 mm were arranged in a 5 × 7 dot matrix was used, and the state where all the dots were illuminated in green, red, and orange was used. The viewing angle is wide for each color having a different wavelength range.

In the above embodiment, the tip of the resin portion 11 of the light emitting diode is a flat surface, but it may be a spherical surface close to a flat surface, or a curved surface such as a cylindrical surface. It may be an arbitrary position up to the tip surface, and the luminous intensity and viewing angle of the light emitting diode can be adjusted by appropriately selecting the shape of the tip surface and the tip position of the reflector. Furthermore, it goes without saying that the plane of the tip of the resin portion may be inclined with respect to the optical axis.

[0025]

As described above, according to the present invention, since the light emitted from the light emitting point is refracted and scattered in multiple directions by the tip of the resin portion, the directional characteristic of the dot matrix type light emitting diode display device is changed. However, a wide viewing angle can be obtained and information can be transmitted to an unspecified number of people in a wide range of places. Further, by applying an antiglare material, light coming from the outside to the light emitting diode is diffusely reflected, and the visibility of display information is improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a dot matrix light emitting diode display device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a dot matrix light emitting diode display device according to another embodiment.

FIG. 3 is a ray tracing diagram of a light emitting diode used in the embodiment.

FIG. 4 is a directional characteristic diagram of a dot matrix type light emitting diode display device according to another embodiment of the same.

FIG. 5 is a table showing the directivity of light emitting diodes using semiconductor elements of different wavelength regions belonging to green, red, and orange in the other example.

FIG. 6 is a cross-sectional view of a conventional dot matrix light emitting device.

FIG. 7 is a cross-sectional view of a conventional all-mold type visible light emitting diode.

FIG. 8 is a directional characteristic diagram of a conventional dot matrix type light emitting diode display device.

[Explanation of symbols]

 3 printed circuit board 8 optical axis 9 light emitting diode 10 reflector 11 resin part 12 antiglare material

Front page continuation (72) Inventor Kenji Suzuki 2-13-13 Toranomon, Minato-ku, Tokyo International Electric Co., Ltd.

Claims (3)

[Claims] 1. In a dot matrix type light emitting diode display device in which a plurality of light emitting diodes are arranged in a dot matrix form on a printed circuit board, the resin portion of each light emitting diode has a flat end, and a space between each light emitting diode is provided. A dot-matrix light-emitting diode display device, characterized in that it is partitioned by a reflector. 2. The dot matrix type light emitting diode display device according to claim 1, wherein an antiglare material is applied to a front end surface of the resin portion of the light emitting diode. 3. The dot matrix type light emitting diode display device according to claim 1, wherein the tip position of the reflector is set to a required position between the light emitting point of the light emitting diode and the tip surface of the light emitting diode.